ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
67 lines
1.6 KiB
Markdown
67 lines
1.6 KiB
Markdown
---
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id: bd7123c9c549eddfaeb5bdef
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title: 使用方括号查找字符串中的第一个字符
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/ca8JwhW'
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forumTopicId: 18341
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dashedName: use-bracket-notation-to-find-the-first-character-in-a-string
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---
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# --description--
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方括号表示法是一种在字符串中的特定`index`（索引）处获取字符的方法。
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大多数现代编程语言，如JavaScript，不同于人类从 1 开始计数。它们是从 0 开始计数，这被称为 <dfn>基于零</dfn> 的索引。
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例如, 在单词 "Charles" 中索引 0 上的字符为 "C"，所以在`var firstName = "Charles"`中，你可以使用`firstName[0]`来获得第一个位置上的字符。
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# --instructions--
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使用方括号获取变量`lastName`中的第一个字符，并赋给变量`firstLetterOfLastName`。
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**提示**
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如果你遇到困难了，不妨看看变量`firstLetterOfFirstName`是如何赋值的。
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# --hints--
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`firstLetterOfLastName`的值应该是`L`。
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```js
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assert(firstLetterOfLastName === 'L');
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```
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你应该使用中括号。
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```js
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assert(code.match(/firstLetterOfLastName\s*?=\s*?lastName\[.*?\]/));
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```
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# --seed--
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## --after-user-code--
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```js
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(function(v){return v;})(firstLetterOfLastName);
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```
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## --seed-contents--
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```js
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// Setup
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var firstLetterOfLastName = "";
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var lastName = "Lovelace";
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// Only change code below this line
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firstLetterOfLastName = lastName; // Change this line
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```
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# --solutions--
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```js
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var firstLetterOfLastName = "";
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var lastName = "Lovelace";
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// Only change code below this line
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firstLetterOfLastName = lastName[0];
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```
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